Purchase Solution

Hypothesis Test Questions

Not what you're looking for?

Ask Custom Question

1 Errors & Significance
A STAT 200 instructor wants to compare the final exam scores of students taught using two different curricula. She obtains a sample of 500 students. She randomly assigns 250 students to a traditional curriculum and 250 students to a new curriculum. It is hypothesized that the new curriculum will lead to higher scores. If there is no significant difference between the exam scores of the different teaching methods, she will continue to teach using the older curriculum. If there is a significant difference, then she will publish a new course using the new curriculum.

a. State the null and alternative hypotheses that the instructor should test. Use μ1 to denote the mean final exam score of students in the traditional curriculum group and μ2 to denote the mean final exam score of students in the new curriculum group.

b. Type I error:
i. What does a Type I error mean in this situation?

ii. What are the consequences of making a Type I error in this scenario?

c. Type II error:
i. What does a Type II error mean in this situation?

ii. What are the consequences of making a Type II error in this scenario?

d. In this scenario, is a Type I or Type II error more serious? Or, are they equally serious? Explain your reasoning.

e. If you were working with this researcher, what alpha level would you use and why?

Assume that the instructor completes this study and finds μ1 = 41 and μ2 = 40 with a pooled standard deviation of 7. Her p-value is 0.0413.

f. Compute Cohen's d as a measure of effect size.

g. Using the alpha level you selected in part e, are her results statistically significant? Explain why or why not.

h. Are her results practically significant? Explain why or why not.

2 Confidence Intervals & Hypothesis Tests
The manager of a restaurant wants to know if there is a correlation between the amount of a customer's bill and the percent that they tip. In other words, as people spend more money, do they tend to tip at different rates? With data from a random sample of 157 receipts, he used StatKey to construct a 95% bootstrap confidence interval for ρ. The results were: [0.018, 0.292].

a. If the manager wanted to conduct a hypothesis test instead, what would be the appropriate null and alternative hypotheses?

b. Based on the 95% confidence interval, would you expect the manager to reject or fail to reject the null hypothesis at the 0.05 alpha level? Explain your reasoning.

c. Using this scenario, compare and contrast confidence intervals and hypothesis testing. List at least one similarity and at least one difference.

3 Hypothesis Tests
A researcher wants to compare the means of 4 different groups. What procedure(s) should he use and why?

Purchase this Solution

Solution Summary

Answered in over 550 words. Explanations have been given for answers. Calculations and statistical notations are shown using Word equation editor. Computed answers have been rounded to 3 decimal places.

Solution provided by:
  • MSc, California State Polytechnic University, Pomona
  • MBA, University of California, Riverside
  • BSc, California State Polytechnic University, Pomona
  • BSc, California State Polytechnic University, Pomona
Recent Feedback
  • "Excellent work. Well explained."
  • "Can you kindly take a look at 647530 and 647531. Thanks"
  • "Thank you so very much. This is very well done and presented. I certainly appreciate your hard work. I am a novice at statistics and it is nice to know there are those out there who really do understand. Thanks again for an excellent posting. SPJ"
  • "GREAT JOB!!!"
  • "Hello, thank you for your answer for my probability question. However, I think you interpreted the second and third question differently than was meant, as the assumption still stands that a person still independently ranks the n options first. The probability I am after is the probability that this independently determined ranking then is equal to one of the p fixed rankings. Similarly for the third question, where the x people choose their ranking independently, and then I want the probability that for x people this is equal to one particular ranking. I was wondering if you could help me with this. "
Purchase this Solution

Free BrainMass Quizzes
Measures of Central Tendency

This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.

Measures of Central Tendency

Tests knowledge of the three main measures of central tendency, including some simple calculation questions.

Terms and Definitions for Statistics

This quiz covers basic terms and definitions of statistics.

Know Your Statistical Concepts

Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.